Rockefeller Group has assembled a site on the south side of 48th between 6th and 7th. All of the buildings are empty, but for one which houses a Dunkin Donuts and another which is a multistory parking garage. SL Green recently bought the corner property which Rockefeller did not control. It houses a Smilers Deli. I would not be surprised if SLG buys the whole site from RG. RG recently sold a development site that it assembled across the street on the north side of 48th. It includes the large bui…